<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    .git{
        height: 1000px;
        overflow: auto;
    }

    .hith{
        position: fixed;
        top: 0;
        left: 0;
    }
    .body{
        background-color: chartreuse;
    }
    .gita{
        position:fixed;
        bottom: 0;
        left: 0;
    }
    .btn{
        width: 40px;
        height: 40px;
        border-radius: 20px;
        background-color: orange;
        position: fixed;
        right: 50px;
        bottom: 80px;   
        /* 子类居中 */
        text-align: center;   
    }
    .btn span{
        color: white;
        
        font-size: 30px;
       
        /* 居中 问题*/
        /* margin-top: 5px;
        margin-left: 5px; */

    }
    </style>
</head>
<body>
    <div class="git">
        <div class="toper"></div>
        <img class="gith" src="../images/giteeHead.jpg" alt="">
        <div class = "body">
            <div class = "main"></div>
            <div class="btn"><span>W</span></div>
        </div>
        <img class="gita" src="../images/giteead1.jpg" alt="">
        <ul>
            <li><a href=""></a></li>
            <li><a href=""></a></li>
            <li><a href=""></a></li>
            <li><a href=""></a></li>
        </ul>
        <a href="ab1"></a>
        <a href="ab2"></a>
        <a href="ab3"></a>
        <a href="ab4"></a>
        <div class="wrapper">
            <ul>
                <li><a href=""></a></li>
                <li><a href=""></a></li>
                <li><a href=""></a></li>
                <li><a href=""></a></li>
            </ul>
        </div>
    </div>
</body>
</html>